Connectify

Connectify lets you turn your laptop into its own hotspot so that others can share your Internet connection. Run the software, and then people within range can use your hot spot to get Internet access.

If you're someplace with only an Ethernet Internet connection, you can bring your friends or co-workers onto that connection by turning your laptop into a hotspot with Connectify. And if you're at a for-pay hotspot, one person can establish a for-pay connection, while the others can then use that single hotspot, so that everyone gets Internet access, while paying for only a single connection.

--Preston Gralla